Interaction region of magnon-mediated spin torques and novel magnetic states* *Project supported by the National Natural Science Foundation of China (Grant No. 61774001), the Natural Science Foundation of Hebei Province of China (Grant No. F2019202141), and the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, China (Grant No. KF201906).

Abstract

We determine the region in which the magnon-mediated spin torques exist. This region can be controlled by the spin waves. In terms of stability analysis of magnetization dynamics based on the spin-wave background, we obtain the instability conditions of spin waves. With these results, we find the relationship between unstable regions and the formation of Akhmediev breather, Kuznetsov–Ma breather and rogue waves. We establish the phase diagram of some novel magnetic excitaions.